Method of measuring alternating electric currents



8 Sheets-Sheet 1.

(No Model.)

0. B. SHALLENBERGER. METHOD OF MEASURING ALTERNATING ELECTRIC GURRBNTS.

No. 449,001. Patented Mar. 24, 1891.

cwmxwkmmm \NVENTOR.

My m W m 1% (No Model.) 8 Sheets-Sheet 2. 0. B. SHALLENBERGER.

METHOD OF MEASURING ALTERNATING ELECTRIC GURRENTS. 'N0. 449,001.Patented Mar. 24, 1891.

WITNESSES:

INVENTOR,

(No Model.) 8 Sheets-Sheet 4.

O. B. SHALLENBERGER. METHOD OF MEASURING ALTERNATING ELEOTRIO OURRENTS.

No. 449,001. Patented Mar. 24, 1891.

\ Ait'ys.

8 SheetsSheet 5,

(No Model.)

0. B. SHALLENBERGER. METHOD OF MEASURING ALTERNATING ELECTRIC GURRENTS.No. 449,001.

Patented Mar. 24, 1891.

' INVENTOR,

o wxvmmw g (N0 Modem v 8 Sheets-Sheet 6. 0. B. SHALLENBERGER.

METHOD OF MEASURING ALTERNATING ELECTRIC GURRENTS. No. 449,001. PatentedMar. 24,- 1891.

WITNESSES: INVENTOR.

0. B. SHALLENBERGER.

METHOD OF MEASURING ALTERNATING ELECTRIC GURRENTS.

No. 449,001. Patented Mar. 24, 1891.

WITNESSES: INVENTOR;

- (No Model.) 8 SheetsSheet 8 0. B. SHALLENBERGER. METHOD OFYMEASURINGALTERNATING ELECTRIC GURRENTS. 7

No. 449,001. Patented Mar. 24, 1891.

WITNESSES: INVENTOR,

.llNrrnn STATES PATE T CFFICE.

OLIVER B. SHALLEN BERGER, OF ROCHESTER, ASSIGNO R, BY MESNE ASSIGN-MENTS, TO THE VESTINGHOUSE ELECTRIC AND MANUFACTURING COM- PANY, OFPITTSBURG, PENNSYLVANIA.

METHOD OF MEASURING ALTERNATING ELECTRIC CURRENTS.

SPECIFICATION forming part of Letters'Patent No. 449,001, dated March24, 1891.

Application filed December 26, 1888. Serial No. 294,568- (No model.)

To all whom, it may concern:

Be it known that I, OLIVER B. SHALLEN- BERGER, a citizen of the UnitedStates, residing in Rochester, in the county of Beaver and State ofPennsylvania, have invented certain new and useful Improvements in theMethod of Measuring Alternating Electric Currents, (Case No. 237,) ofwhich the following is a specification.

My invention relates to certain improvements in the method ofmeasuringthe electric currents consumed in doing useful work uponalternating-current circuits.

The object of the invention is to provide a method whereby a meter maybe caused to register only the current consumed in doing useful work,while it is not operated by the leakage-current which may flow in thecircuits, or by such current as may be consumed in any other operationthan doing useful work. Such a method of measuring currents isespecially desirable in connection with circuits employing electricconverters or transformers, for the reason that there is practicallymore or less leakage through the primary coils of the converters evenwhen their secondary circuits are open, and therefore unless specialmeans are employed to guard against it the meter placed in the primarycircuit would record the flow of such currents and might be continuallyoperated, even though no useful work were being done.

My invention. consists in so organizing a meter designed to be connectedin the primary or supply circuitor to measure the current flowingthrough it that it will commence to operate only when the flow ofcurrent through the circuit to which it is applied exceeds the leakageof the circuit or of the converters connected in the circuit, and at thesame time will give an accurate record of all the current consumed indoing useful work.

There are several diiferent plans which may be adopted in carrying outthe invention, certain of which will be described in connection with theaccompanying drawings.

In the drawings, Figure 1 illustrates an or-' ganization in which themeter itself is so constructed that the current necessary to start itexceeds the leakage of the circuit to which y it is applied. Fig. 2illustrates an organization in which a converter is introduced betweenthe meter and the circuit. This converter requires a current having adefinite relation to the leakage-current to place it in such a magneticcondition as to yield current to the meter. Fig. 3 illustrates anorganization in which a mechanical detent is employed. for arresting themovement of the meter until a current of predetermined value is flowing.Fig. 4 illustrates the application of a thermostat for arresting themeter until a current of a predetermined value is flowing. Fig. 5 showsa plan of short-oircuiting the meter-coils, except when the currentexceeds apredetermined amount. Fig.6 showsa plan of employing aresistance for diminishing the torque exerted by the current on the diskuntil a current of a predetermined value is reached. Fig. 7 illustratesa method of securing an automatic adjustment of the relative positionsof two actuating-coils of a special form of meter in such manner that itwill start only when a predetermined current flows. Fig. 8 illustrates aspecial construction of the armature of a meter which requires a currentof a definite value to startit.

Referring to the figures, G represents any suitable source ofalternating, intermittent, or pulsatory electric currents, and L Lconductors leading from the respective poles thereof to a work-circuitIV. In this workcircuit any required number of converters ortransformers are connected, as shown at C C C. The primary coils ofthese converters 8 5 are connected in multiple arc, and their secondarycoils supply current to translating devices d, which may be placed incircuit or removed therefrom, as required, in any convenient well-knownmanner. More or less current will pass through the primary coils of theconverters even when their secondary circuits are open. This current isusually termed the leakage-current. The percentage of current thusconsumed is very small; but it becomes appreciable when severalconverters are connected in multiple. It is evident that when a consumerpays for the current by reference to a meter it would not be proper torecord upon the meter the current consumed by the leakage of theconverters,

but only that used in doing useful work in the secondary circuits. Toavoid this the meter is constructed so that it will respond only 5 whenthis leakage upon the circuit to which it is applied is exceeded, or, inother words, only when current is allowed to flow through the secondarycoils of one or more of the converters.

The invention is applicable to various different forms of meters; butfor convenience of description it will be set forth more particularly inconnection with an electric meter of the construction described incertain patents issued to me August l-i,1S8S,Nos. 388,003 and 388,00t.The application of the invention to other forms of meters than this willbe apparent when considered in connection with the descriptionshereinafter given.

In the meter described in the patents referred to the armature A isrevolved by the resultant effects of currents traversing two coils B and(l. The coil Bis of insulated conducting material, and in theorganization shown in Fig. 1 it is connected in the main- -lineconductor L. Currents are induced in the conductor C in this instance bycurrents flowing in the conductor 13. The armature A tends to revolveunder the influence of the 0 lines of polarization established by thecurrents traversing these two coils. By properly proportioning the coilsand relating them to eachother and to the armature the current requiredto overcome the friction or inertia ot' the meter may be made to exceedthat which will leak through the primaries of the converters when nocurrent is flowing. Thus if the leakage in the present instance isone-tenth of an ampere for each con- 40 verter and there are threeconverters connected in multiple are, then the meter is so constructedthat it will not respond to a current of three-tenths of an ampereflowing through the work-circuit. This current, howover, is suflicientto place the meterin condition to be started upon the slightest increaseof current. Therefore, if the secondary circuit of any converter beclosed through one or more translating devices, the meter willimmediately respond and record the current ilowing in the main line inexcess of that flowing when no work is being done in the secondaries. Inother words,the currentrequired to set the meter in motion and to causeit to register is equal to or slightly exceeds that which leaks throughthe feeders when no work is being done in the secondary circuit.

As the current flowing increases, the armature will rotate withincreasing velocity, and as the velocity increases the rotating effectproduced by a given increase of current also increases.

In order that the indications of the meter may be proportional to thecurrent supplied to the work-circuit, a retarding effect must beintroduced, which will increase in Value by the same law as the increasein the rotating effect. The desiredretardation may be obtained byapplying to the shaft vanes or fans N, (see Fig. 3,) the retardingeffect of which will increase under increasing velocities. Therevolution of the armature may be recorded upon the dials in the mannerdescribed in the patents referred to.

In Fig. 2 another plan of carrying out the invention is illustrated, inwhich, instead of constructing the meter itself so that itsstarting-current is equivalent to the leakage, the current is deliveredto the meter through a converter 0, which is constructed to have apredetermined leakage somewhat less than the sums of the leakages of theseveral convcrters G C C connected in the work-c1rcuit, while the meteritself is constructed to require a starting-current equivalent to thedifference between the leakage of the converter O and the sum of theleakages of the several work-circuit converters. Thus if the leakage inthe work-circuit amounts to fourtenths of an ampere the converter 0 mayhave a leakage of two-tenths of an ampere-that is to say, a current oftwo-tenths of an ampere may flow through its primary before any currentis induced in the secondary. Then when acurrent of four-tenths of anampere is flowing through the primary a current of two-tenths will beinduced in the secondary, providing that the ratio of conversion of theconverter is unity. The meter itself should then be so constructed thata current of two-tenths of an ampere would place it 111 readiness tostart upon any increase of 'current. The operation of the apparatuswould then be essentially the same as that already described inconnection with Fig. 1. In this organization, however, another factormust be taken into considerationnamely, the varying percentage ofleakage in the converter 0-:- for as the current flowing to thework-circuit increases, the leakage through the converter 0 alsoincreases since it. is connected in series with the work-circuit, and isconsequently subjected to a higher diil'erencc of potential. The currentdelivered to the meter therefore is not directly proportionate to thecurrent flowing, and it becomes necessary to compensate in the meter forthis increasing leakage of the converter 0. This may be accomplished byproperly proportioning the elements of the meter itself. Thusthearmature maybe constructed to revolve with greater rapidity under givenincrements of current as the velocity increases-that is to say, thetorque may be made to increase in greater ratio relatively to thecurrent than the retarding effect relatively to the speed. This resultmay be accomplished, for example, by decreasing the magnetic saturationof the armature. As the armature approaches more nearly to a conditionof saturation the torque increases less rapidly.

In the organization showuin Fig. 3 the u1eter is constructed to benormally held at rest by a stop of any suitable character, which willICO a be thrown away from the armature when the current flowingthroughthe metcrexceeds the leakage of the work-circuit. In this instance thestop is shown at b and consists merely of an arm intercepting the pathof the fans N. It is carried in this instance by the movable core a of asolenoid a, which is connected in series with the coils B. As thecurrent through the coils B and the solenoid increases, the core isdrawn farther into the solenoid, and thus the stop is withdrawn from thepath of the vanes or some other moving part of the meter When thecurrent attains the proper value. This construction does not necessitateany initial leakage on the partof the meter itself. Other methods ofapplying the stop will be evident.

In Fig. I an organization is illustrated wherein a thermostatic deviceisemployed for arresting the motion of the meter until the current hasreached a predetermined value. The thermostatic device consists of twostrips of metal 71 k having different rates of expansion under theinfluence of heat. The strips are insulated from each other throughouttheir lengths and secured, respectively, to plates K K at one end. Theopposite ends are in electrical connection with each other.

' The two strips are connected in circuit in se ries, the conductor Lbeing led to the block K, while the block K is connected with the coilsB. When little or no currentis passing through the thermostatic device,a detent 70, carried atthe free end, rests against the armature andprevents it from revolvin As the current increases, however, and theleakage of the current is exceeded,sufticientheat is developed by itspassage through the thermostatic strips to cause them to bend away fromthe armature, thus releasing it and allowing the meter to operate. Itwill be observed that the thermostatic device is operated by the heatdeveloped in itself by the current passing through the two strips.

In Fig. 5 an organization is illustrated wherein the meter isshort-circuited so long as the leakage-current or the current which itis not desired to record is flowing through the circuit. This isaccomplished by connecting an electro-magnet or solenoid m in serieswith the meter. This solenoid is provided with a core m, carried uponone end of a movable lever m the other end of which carries a circuitclosing point m This point passes between two contact-springs m and on,which are, respectively connected with the terminals of the meter. lVhenthe current exceeds a predetermined value, the core is drawn into thesolenoid against the opposition of a spring 8 a sufficient distance toseparate the circuit-closing point from the contact-points, and thusinterrupt the shuntcircuit around the meter and allow it to operate. Thesolenoid still remains in circuit, and thus holds the shunt-circuitopen.

In Fig. 6 an organization is illustrated wherein the secondary coil C isclosed through a resistance R. The resistance opposes the passage ofcurrent through the coil to such .an extent that normally the meter willnot pendently of the resistance R, whereupon .the meter operates.

In Fig. 7 an automatic adjusting device for the coil 0 is shown. Theplanin this instance is to automatically vary the angle of the coil 0 withreference to the coil I3. The coil 0 normally stands in such positionthat the inductive effects upon it from currents traversing the coil Bare such that the meter will re quire a large current to start it. Asolenoid T is included in series with the coil B, and its core I. isattached to an arm carried by the movable secondary coil 0. As thecurrent in the main circuit increases, the core is drawn a greaterdistance into the solenoid, t-hus turning the coil upon its axis into aposition more favorable for receiving currents by induction and foracting upon the armature of the meter. If the secondary coil is made toturn very freely on its supports, the coil T and core t may be dispensedwith. The movement will then take place from the direct action of thecoils B.

Fig. 8 represents an organization wherein the armature is so constructedthat when at rest it has a tendency to stand in a given position withreference to the coil 0, and while in that position it requires apredetermined initial current to set it in motion. The inertia oncebeing overcome, the armature will continue to revolve with increasingrapidity as the current increases. To accomplish this the armature iscut away upon two sides, as shown at a a so that the diameter is greaterin the direction x The armature will therefore stand in the positionshown in the drawings so long as the current flowing is insufficient toovercome the tendency of the armature to set itself in this position.This tendency may be augmented by placing a copper band in around thearmature in such direction that the polar line established by theinduced currents circulating in it will be in the direction 00 so. Theeffect of this is to lessen the torque exerted upon the armature so longas it stands in the position shown in the drawings; but when once set inrevolution it will continue to revolve readily under the influence ofthe current flowing.

It is evident that the invention here described and claimed isapplicable to other meters than that described, and it is evident, also,that different methods of applying the invention to the particular meterhere shown may be adopted; but those already described are sufficientfor a full and complete understanding of the invention.

I claim as my invention- 1. The hereinbefore-described method ofmeasuring the currents consumed in doing useful work. inalternating-ciu'rent electric circuits, which consists in employing theleakage-current of the circuit to overcome the inertia of the meter andin operating the meter by the current flowing in excess of suchleakage'enrrent.

2. The l1ereinbefore-describcd method of measuring the currents consumedin doing useful work in an electric circuit-,which con sists inemploying the leakage-current of the circuit to place the meter incondition to be operated, operating the meter by the current flowing inexcess of such leakage-current, and in causing the rate of movement ofthe

